Article

Autoantibodies to Nervous System-Specific Proteins Are Elevated in Sera of Flight Crew Members: Biomarkers for Nervous System Injury

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Abstract

This descriptive study reports the results of assays performed to detect circulating autoantibodies in a panel of 7 proteins associated with the nervous system (NS) in sera of 12 healthy controls and a group of 34 flight crew members including both pilots and attendants who experienced adverse effects after exposure to air emissions sourced to the ventilation system in their aircrafts and subsequently sought medical attention. The proteins selected represent various types of proteins present in nerve cells that are affected by neuronal degeneration. In the sera samples from flight crew members and healthy controls, immunoglobin (IgG) was measured using Western blotting against neurofilament triplet proteins (NFP), tubulin, microtubule-associated tau proteins (tau), microtubule-associated protein-2 (MAP-2), myelin basic protein (MBP), glial fibrillary acidic protein (GFAP), and glial S100B protein. Significant elevation in levels of circulating IgG-class autoantibodies in flight crew members was found. A symptom-free pilot was sampled before symptoms and then again afterward. This pilot developed clinical problems after flying for 45 h in 10 d. Significant increases in autoantibodies were noted to most of the tested proteins in the serum of this pilot after exposure to air emissions. The levels of autoantibodies rose with worsening of his condition compared to the serum sample collected prior to exposure. After cessation of flying for a year, this pilot's clinical condition improved, and eventually he recovered and his serum autoantibodies against nervous system proteins decreased. The case study with this pilot demonstrates a temporal relationship between exposure to air emissions, clinical condition, and level of serum autoantibodies to nervous system-specific proteins. Overall, these results suggest the possible development of neuronal injury and gliosis in flight crew members anecdotally exposed to cabin air emissions containing organophosphates. Thus, increased circulating serum autoantibodies resulting from neuronal damage may be used as biomarkers for chemical-induced CNS injury. The authors thank all of the participants who volunteered to take part in this case study. The technical work of Dr. Hagir B. Suliman and the art work of Sheref M. Abou-Donia are appreciated. This study was supported in part by the Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina, USA.

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... Higher levels of circulating autoantibodies compared to matched controls were found in flight crew who complained of ill health following exposure to contaminated air (Abou-Donia et al., 2013;Abou-Donia and Brahmajothi, 2020). From our own studies a pilot was tested after a set of 31 Aerotoxic syndrome flights spending 45 h in the cockpit during 10 days. ...
... This suggests that autoantibody testing may be a valuable marker of nervous system injury in aerotoxic syndrome. In our cases MBP, MAP-2 and GFAP were most abnormal (Abou-Donia et al., 2013;Hageman et al., 2020a,b). ...
... In some cases, balance problems, muscle fasciculations and reduced sensation were noted. Paresthesia of the hands were reported in about 30% of flight crew 32 G. Hageman et al. members (Abou-Donia et al., 2013;Somers, 2005). One frequently used test is vibration sensitivity, which evaluates peripheral somatosensory function. ...
Chapter
The term aerotoxic syndrome has been proposed to describe a constellation of symptoms reported by pilots and cabin crew following exposure to possible (neuro)toxic substances in cabin air. Several organ systems are involved. Potentially toxic chemicals emanate from hydraulic fluids and engine oil and include organophosphate compounds, solvents and carbonmonoxide. Oil contamination in the compressor will result in nanoparticles in bleed air under most operating conditions. Overfilling of oil or faulty seals lead to oil leaks which permit ultrafine particles to cross oil seals. Extremely high temperatures in aircraft engines may alter the composition of the original oil and create new toxic compounds. De-icing fluids and the use of insecticides may also contaminate cabin air. Regulatory authorities estimate fume events (incidental smells, smoke or mist inside an airplane) happen on 0.2–0.5% of flights. Objective evidence of exposure is often lacking and indirect proof in the form of biomarkers is scarce. The underlying mechanisms leading to chronic symptoms, extend beyond cholinesterase inhibition. Individual genetic differences in the ability to metabolize solvents and organophosphates may explain why long-term intermittent low-level exposure causes ill health in some people. We discuss the current evidence for central nervous system injury in aerotoxic syndrome and propose diagnostic criteria to argue for its recognition as occupational disorder. Prospective studies and a proactive attitude of authorities are required. Nano-aerosols as vehicles for toxic compounds should stimulate the development of bleedless aircraft. Until then the “aircraft cabin of the future” should have continuous cabin air monitoring and filter technology to make flying safe for everyone.
... At that time, extensive blood tests were again normal, including negative immunological studies (ACE, rheumatoid factor, ANA, and ANCA) and MRI examination of head and spine, nerve conduction studies, and EMG were also normal. A blood sample submitted to Duke University showed highly positive results for autoantibodies against myelin basic protein (MBP), neurofilament proteins, microtubule-associated tau proteins, tubulin, and microtubule-associated protein-2 (MAP-2), all biomarkers for neuronal degeneration [11]. Moreover, high levels of autoantibodies against glial fibrillary acidic protein and the glial calcium-binding protein S-100B, both astrocytic markers for brain injury, were also observed. ...
... Blood tests and neurological evaluation had been normal, except for subtle findings on a brain scan of a low pulsatility of sylvian and thalamic arteries. A blood sample submitted to Duke University showed a highly significant increase in myelin-associated glycoprotein [11]. The results of all her Fig. 1 a, Bilateral erythema and inflammation of ear skin and cartilage (auricular chondritis) after exposure to aircraft fumes. ...
... Both MRI examination and nerve conduction studies do not demonstrate any relevant abnormalities in AS cases [1]. However, increased levels of autoantibodies against neuronal and/or glial proteins, as found in our cases 1 and 3, would be consistent with non-specific chemical-induced nervous system injury [11]. ...
Article
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PurposeCase series on respiratory features of Aerotoxic Syndrome (AS). The term AS has been coined to describe the spectrum of clinical manifestations after aircraft fume events. Among these manifestations, neurological and respiratory symptoms are the most frequently reported complaints.Methods Three cases of AS with relevant respiratory features are presented.ResultsCough and shortness of breath for 6 to12 months were the predominant symptoms in the first two cases. The first case also developed neurological symptoms affecting his central nervous system. In the third case, the patient complained for nine years about an unbearable cough triggered by odors, smells, and a variety of indoor and outdoor irritants, among other symptoms of multiple chemical sensitivity. In all three cases, the respiratory symptoms resolved after appropriate treatment.Conclusion Our report aims at raising awareness on AS and calls for actions to improve the management of patients suffering from this syndrome.
... The specificity of the serum autoantibody against all tested neural proteins was carried out by performing a protein/peptide absorption assay. Previously, we have checked the specificity of the serum autoantibody levels by performing an absorption assay, where the serum was preincubated with the target protein or peptide [26]. In this study, we used the serum from ASD children and control children, where we incubated the sera overnight at 4°C with S100B, GFAP, tau, MAP2, NFP, tubulin, MBP SNCA or MAG. ...
... Sera were analyzed by western blot analysis. The specificity of autoantibody in the sera was assessed by performing peptide/antigen absorption assay by preabsorbing the serum with the target proteins [26]. The preabsorbed serum of ASD patient was tested by western blot (Figure1). ...
... The results of this study suggest that the profile of the peripheral autoantibodies against the neural proteins is unique to ASD children as compared to the profiles found in other brain disorders [30]. Our previous studies documented the presence of IgG autoantibodies against neuronal and glial proteins in sera of aircrews and farm workers who were exposed to organophosphates (OP) and developed OP-induced delayed neurotoxicity(OPIDN) as well as the following exposure to molds [26,31,32]. A recent study from another laboratory-confirmed our finding in another cohort of aircrews using Magnetic Resonance Imaging (MRI) examination [33]. ...
Article
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Autism spectrum disorders (ASDs) are the most common neurodevelopmental disorders with unidentified etiology. The behavioral manifestations of ASD may be a consequence of genetic and/or environmental pathology in neurodevelopmental processes. In this limited study, we assayed autoantibodies to a panel of vital neuronal and glial proteins in the sera of 40 subjects (10 children with ASD and their mothers along with 10 healthy controls, age-matched children and their mothers). Serum samples were screened using Western Blot analysis to measure immunoglobulin (IgG) reactivity against a panel of 9 neuronal proteins commonly associated with neuronal degeneration: neurofilament triplet proteins (NFP), tubulin, microtubule-associated proteins (tau), microtubule-associated protein-2 (MAP-2), myelin basic protein (MBP), myelin-associated glycoprotein (MAG), α-synuclein (SNCA) and astrocytes proteins such as glial fibrillary acidic protein (GFAP) and S100B protein. Our data show that the levels of circulating IgG class autoantibodies against the nine proteins were significantly elevated in ASD children. Mothers of ASD children exhibited increased levels of autoantibodies against all panel of tested proteins except for S100B and tubulin compared to age-matched healthy control children and their mothers. Control children and their mothers showed low and insignificant levels of autoantibodies to neuronal and glial proteins. These results strongly support the importance of anti-neuronal and glial protein autoantibodies biomarker in screening for ASD children and further confirm the importance of the involvement of the maternal immune system as an index that should be considered in fetal in utero environmental exposures. More studies are needed using larger cohort to verify these results and understand the importance of the presence of such autoantibodies in children with autism and their mothers, both as biomarkers and their role in the mechanism of action of autism and perhaps in its treatment.
... Once in circulation, autoantibodies are formed to these proteins. Such autoantibodies represent emerging biomarkers for brain damage (Evans 1995;Abou-Donia et al. 2013, 2017. Protein fragments from injured neuronal and glial cells can be found in the cerebrospinal fluid (CSF), however, their detection in CSF is a complicated and highly invasive maneuver. ...
... To screen for the presence of autoantibodies against a battery of proteins, we applied a western blot approach as previously reported (Abou-Donia et al. 2013). Each serum sample was analyzed in triplicate. ...
... Previously, we checked the specificity of the serum autoantibody by performing peptide/antigen competition assay, in which the serum was spiked with the target protein or peptide (Abou-Donia et al. 2013). The serum from random healthy controls was mixed with or without tau, MAP, or MBP. ...
Article
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In the present study, we screened the sera of subjects chronically exposed to mixtures of pesticides (composed mainly of organophosphorus compounds (OPs) and others) and developed neurological symptoms for the presence of autoantibodies against cytoskeletal neural proteins. OPs have a well-characterized clinical profile resulting from acute cholinergic crisis. However, some of these compounds cause neuronal degeneration and demyelination known as organophosphorus compound-induced delayed neurotoxicity (OPIDN) and/or organophosphorus compound-induced chronic neurotoxicity (OPICN). Studies from our group have demonstrated the presence of autoantibodies to essential neuronal and glial proteins against cytoskeletal neural proteins in patients with chemical-induced brain injury. In this study, we screened the serum of 50 pesticide-exposed subjects and 25 non-exposed controls, using Western blot analysis against the following proteins: neurofilament triplet proteins (NFPs), tubulin, microtubule-associated tau proteins (Tau), microtubule-associated protein-2 (MAP-2), myelin basic protein (MBP), myelin-associated glycoprotein (MAG), glial fibrillary acidic protein (GFAP), calcium-calmodulin kinase II (CaMKII), glial S100-B protein, and alpha-synuclein (SNCA). Serum reactivity was measured as arbitrary chemiluminescence units. As a group, exposed subjects had significantly higher levels of autoantibody reactivity in all cases examined. The folds of increase in of autoantibodies against neural proteins of the subjects compared to healthy humans in descending order were as follows: MBP, 7.67, MAG 5.89, CaMKII 5.50, GFAP 5.1, TAU 4.96, MAP2 4.83, SNCA 4.55, NFP 4.55, S-100B 2.43, and tubulin 1.78. This study has demonstrated the presence of serum autoantibodies to central nervous system-specific proteins in a group of farmers chronically exposed to pesticides who developed neurological signs and symptoms of neural injury. These autoantibodies can be used as future diagnostic/therapeutic target for OP-induced neurotoxicity.
... Due to their widespread use as pesticides, plasticizers and flame retardants organophosphates are routinely detected in environmental samples. However, a specific concern has arisen in recent decades as aircraft crew have developed symptoms consistent with exposure to toxic fumes and organophosphates (Abou-Donia et al., 2013;Harrison and Mackenzie Ross, 2016;Liyasova et al., 2011;Payne, 2015). There have been reports of headaches, loss of balance, numbness and neurobehavioral abnormalities such as emotional instability, depression and cognitive dysfunction, including impaired short term memory, blurred vision and speech, altered coordination (de Ree et al., 2014;Abou-Donia et al., 2013). ...
... However, a specific concern has arisen in recent decades as aircraft crew have developed symptoms consistent with exposure to toxic fumes and organophosphates (Abou-Donia et al., 2013;Harrison and Mackenzie Ross, 2016;Liyasova et al., 2011;Payne, 2015). There have been reports of headaches, loss of balance, numbness and neurobehavioral abnormalities such as emotional instability, depression and cognitive dysfunction, including impaired short term memory, blurred vision and speech, altered coordination (de Ree et al., 2014;Abou-Donia et al., 2013). ...
... There is evidence to indicate that aircraft crew and passengers have been exposed to organophosphates from traveling on aeroplanes and that it has resulted in neurotoxic effects (Abou-Donia et al., 2013;Liyasova et al., 2011). Abou-Donia et al. (2013) undertook a study of 34 flight crew members and the results suggest the possible development of neuronal injury and gliosis in flight crew members anecdotally exposed to cabin air emissions containing organophosphates. ...
Article
Fresh and used aircraft engine lubricants (Mobil Jet Oil II) were analysed using a Fourier Transform Ion Cyclotron Resonance Mass Spectrometer (FTICRMS) and comprehensive two dimensional gas chromatography with high resolution time of flight mass spectrometry (GCxGC-HRTOFMS). The composition of the fresh oil was established, with special focus to its tricresyl phosphate (TCP) content as this has formed the focus for most investigations into aerotoxic syndrome. The results showed that only four TCP isomers were present at detectable levels in the fresh oil: mmm-TCP, mmp-TCP, ppm-TCP and ppp-TCP. The results indicate that the formulation of Mobile Jet Oil II does not contain the more toxic ortho substituted TCP isomers at concentrations above 0.0005%. The temperatures of jet engines during operation are greater than 200 °C which creates the potential to alter the composition of the original oil and create other toxic compounds. The results show there may be a significant risk from alkylated cresyl phosphates, which were identified in the used oils at concentrations calculated in the range of 0.13–0.69%. w/w. Several xylenyl and ethylphenyl phosphates have been shown to exhibit a similar toxicity to ortho substituted TCP isomers which makes there discovery in used oil significant. These compounds should be included in future aircraft air quality studies and when assessing the risks and causes of aerotoxic syndrome.
... Due to the use of TCPs in these applications, human exposure to TCPs could occur in occupational settings, e.g. in the cockpit and cabin of aircraft as a result of leakage of engine oil into the air conditioning systems during flight. The possibility of such exposures to TCP isomers in cabin air has led to concerns among airline crew members since it has been suggested that exposure to ToCP may affect the health of pilots and cabin personnel, resulting in the so-called Aerotoxic syndrome (Winder et al., 2002;Ross, 2008;Furlong, 2011;Abou-Donia et al., 2013). Possible exposure to TriCresyl Phosphates (TCPs) has led to concerns among airline crew members. ...
... In a recent exploratory study, auto-antibodies in serum against a number of proteins present in the (central) nervous system were measured (Abou-Donia et al., 2013). These auto-antibodies may be formed and released into the bloodstream upon damage to the cells of the nervous system. ...
... However, whether this also holds for (chronic) chemically-induced neurotoxicity needs to be confirmed. More importantly, the control group in the study from Abou-Donia et al. (2013) may not be very appropriate as it has no connection with aviation industry and also is not suffering from any CNS-related complaints. It therefore remains to be confirmed if the presence of auto-antibodies is associated with flying, with CNSrelated complaints, or both. ...
... O,o,o-TCP is metabolized to cresyl saligenin phosphate, a potent irreversible inhibitor of butyrylcholinesterase and acetylcholinesterase (Carletti et al., 2013). Abou-Donia et al. (2013) system-specific proteins and suggested the possible development of neuronal injury and gliosis in flight crew members exposed to cabin air emissions containing organophosphates. The neurotoxicity of TCP is also called organophosphorus-induced delayed neuropathy (OPIDN) as typically a delay of 1-2 weeks or more occurs between exposure and the appearance of effects (Craig and Barth, 1999). ...
... This is another subject for further study and will be important for the establishment of safety factors of thresholds for TCP. A real breakthrough of the work of Abou-Donia et al. (2013) is the prove of the presence of proteins in blood of crew members that are indicators for brain damage. These specific proteins were not present in blood of the control group, consisting of persons not associated with or involved in air service. ...
... The high altitude and lower air pressure at the flight deck and in the cabin may have an influence on the toxic mechanism of TCP. Recent work of Abou-Donia et al. (2013) shows that health complaints of pilots are clinical symptoms that should be taken seriously and call for further studies. These should include better quality toxicity studies, preferably on TCP in the vapor phase. ...
Article
Tricresyl phosphate (TCP), and in particular its tri-ortho substituted isomer (o,o,o-TCP), has been frequently used in aircraft engine oil. Bleed air, provided to the flight deck and cabin can contain traces of TCP. TCP can cause neurotoxic effects in humans. Regularly, airline pilots complain about loss of memory, headaches, dizziness, tunnel vision and other neurotoxic effects. The concentrations of TCP reported in flight deck air (max. ca. 50-100ngm(-3) total TCP) do not exceed provisional toxicity thresholds. These thresholds, however, contain a very high uncertainty and need further underpinning. The many non-detects and relatively low TCP concentrations reported suggest that TCP on its own is not likely to be responsible for the reported health problems of pilots. Specific conditions in air planes and other toxic compounds present in bleed air, whether or not in combination with TCP, may be responsible for the reported neurotoxic syndromes. Sensitivity of individuals seems to be an important factor as well. The clinical signs observed with a selected group of pilots are serious enough to call for further elucidation of this issue.
... Adverse effects being reported by aircrew in relation to exposures to aircraft supply air contamination include a range of both acute and chronic effects that is being labelled primarily as a discrete occupational health condition increasingly termed ' Aerotoxic Syndrome' [4][5][6][7][8][9]. The diffuse pattern of acute and chronic effects include the following areas: neurological, neurobehavioural, respiratory, cardiovascular, gastrointestinal, general (fatigue, Open Access *Correspondence: susan@susanmichaelis.com 1 Occupational and Environmental Health Research Group, University of Stirling, Stirling, UK Full list of author information is available at the end of the article rheumatological, chemical sensitivity, performance decrement, soft tissue), irritant and skin [6]. ...
... The pattern of symptoms reported included a diffuse range of acute and chronic effects include the following areas: neurological, neurobehavioural, respiratory, cardiovascular, gastrointestinal, general (fatigue, rheumatological, chemical sensitivity, performance decrement, soft tissue) irritant and skin [6]. Similar patterns have been increasingly reported elsewhere [4,5,9,[57][58][59][60][61][62][63][64][65][66][67][68]. The FAA reported a range of similar adverse effects as well as delayed effects could be expected following exposure to the complex mixtures associated with pyrolysed jet oils [53]. ...
Article
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Background Airline crew members report adverse health effects during and after inhalation exposure to engine oil fumes sourced to the air supply system onboard commercial and military aircraft. Most investigations into the causal factors of their reported symptoms focus on specific chemical contaminants in the fumes. The adverse health effects reported in aircrew exposed to the aircraft air supply, bled unfiltered off the engine or Auxiliary Power Unit (APU) may be related to particulate exposures, which are widely known to effect health. While oil contaminates the aircraft air supply, some suggest that this will only occur when there is a bearing seal failure, others document that there is low level oil contamination of the air supply during normal engine operation. This brief pilot study explores whether particulate exposure may be associated with the normal engine/APU and air supply operation and to therefore increase the understanding that UFP exposures may have on crew and passengers. Methods An ultrafine particle counter was utilised by an experienced airline captain in the passenger cabin of four short-haul commercial passenger aircraft. All flights were under 90 min on aircraft from two different carriers ranging from 7 months to 14 years old. Results UFP concentrations showed maximum concentrations ranging from 31,300 to 97,800 particles/cm ³ when APU was selected on as a source of air on the ground and with engine bleed air and the air conditioning packs selected on during the climb. In 2 of the 4 flights the peaks were associated with an engine oil smell. Increases in UFP particle concentrations occurred with changes in engine/APU power and air supply configuration changes. Conclusions This study identified increases in UFP concentrations associated with engine and APU power changes and changes in air supply configuration. These results correlated with times when engine and APU oil seals are known to be less effective, enabling oil leakage to occur. The concentrations reached in the passenger cabins exceeded those taken in other ground-based environments. UFP exposures in aircraft cabins during normal flight indicates there will be health consequences for long serving aircrew and some passengers.
... Previously, we have checked the specificity of the plasma and serum autoantibody by performing a peptide/antigen competition assay, in which the serum and plasma were spiked with the target protein or peptide [34]. The serum from random healthy controls was mixed with or without tau, MAP2, or MBP. ...
... Investigations into the mechanisms by which OP compounds cause neurodegeneration have established that OPs increase the activity and expression of calcium-calmodulin Kinase II (CaMKII) that causes hyperphosphorylation of neural proteins, leading to their aggregation and slowing of axonal transport, resulting in neuronal cell death [51,[59][60][61][62]. In agreement with this is our prior finding that airline crews who were exposed to OPs developed autoimmune antibodies to neural proteins 34 . Increased autoantibodies to neuronal proteins such as Tau, NFP, MAG, MBP, and GFAP are consistent with the brain imaging study in another cohort of airline crews which showed decreased brain white matter microstructure and cerebral perfusion, which may be potential causes of cognitive impairments and mood deficits reported by the aircrews [63]. ...
Article
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Veterans from the 1991 Gulf War (GW) have suffered from Gulf War illness (GWI) for nearly 30 years. This illness encompasses multiple body systems, including the central nervous system (CNS). Diagnosis and treatment of GWI is difficult because there has not been an objective diagnostic biomarker. Recently, we reported on a newly developed blood biomarker that discriminates GWI from GW healthy controls, and symptomatic controls with irritable bowel syndrome (IBS) and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). The present study was designed to compare levels of these biomarkers between men and women with GWI, as well as sex-specific effects in comparison to healthy GW veterans and symptomatic controls (IBS, ME/CFS). The results showed that men and women with GWI differ in 2 of 10 plasma autoantibodies, with men showing significantly elevated levels. Men and women with GWI showed significantly different levels of autoantibodies in 8 of 10 biomarkers to neuronal and glial proteins in plasma relative to controls. In summary, the present study addressed the utility of the use of plasma autoantibodies for CNS proteins to distinguish among both men and women veterans with GWI and other healthy and symptomatic control groups.
... Patient A is a 50-year-old pilot, who worked for two (Dutch) commercial airline companies for more than 20 years, with 16 years of intercontinental flights. This patient was one of a case series of 34 flight crew members published in 2013, in which results of assays to detect auto-antibodies were described [3]. He was subsequently referred to our department for further evaluation of his complaints which onset gradually over a period of around 14 years. ...
... In our patients MBP, MAP-2 and GFAP were increased in all three, whereas S-100ẞ was normal in all. Our findings were consistent with those reported in a study of 34 flight crew members in which auto-antibodies against MAP-2, tubulin, MBP, tau and GFAP were markedly elevated, whereas auto-antibodies against S-100 ẞ (a biomarker for traumatic brain injury) were (almost) normal, as in our cases [3]. Sera of the 12 healthy controls had no or low levels of circulating autoantibodies. ...
Article
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Introduction: “Aerotoxic syndrome” is a debated entity. Regulatory authorities consider long-term health effects to be an unlikely consequence of exposure to contaminated air because several air quality monitoring studies report low concentrations of toxic chemicals in cabin air. We describe two pilots and one flight attendant, who developed ill health during their flying career which improved after cessation of flying. Case details: The most frequently reported symptoms were headache, balance problems, fatigue, gastro-intestinal complaints and cognitive impairment. One of these patients had reduced levels of butyrylcholinesterase after a flight suggesting exposure to organophosphate compounds had occurred. All three were found to have elevated neuronal and glial auto-antibodies, biomarkers of central nervous system injury, and all three had genetic polymorphisms of paraoxonase (PON-1) and two of cytochrome P450, leading to a reduced ability to metabolize organophosphate compound (OPs). Discussion: A similar constellation of symptoms has been described in other studies of aircrew, although objective evidence of exposure is lacking in most of these studies. Reduced levels of butyrylcholinesterases in one of our cases is suggestive of causation and elevated neuronal and glial autoantibodies provide objective evidence of damage to the central nervous system. We consider further research is warranted.
... Blood levels of autoantibodies-binding neural antigens have been related to acute and chronic stress (Andrejević et al., 1997;Zhou et al., 1999), and could both reflect and affect neuronal functioning (Gold et al., 2012). Myelin basic protein (MBP) is an important protein in the process of myelination of nerves in the nervous system, and it has been found that high levels of autoantibodies to MBP and other neural antigens were associated with neurological damage (Abou-Donia et al., 2013). Other studies reported relations between stress and autoantibodies-binding antigens reflecting cell damage and inflammation, such as phosphorylcholine (PC) (Lutz et al., 2009). ...
... First, the higher antibody levels may be related to the effects of enrichment on brain and behaviour of pigs, including their mental state. In humans, it has been suggested that emotional states, for instance anxiety and depression, could trigger immune alterations (Postal and Appenzeller, 2015), which may, in turn, affect (neural) cell injury, and as a consequence the release of cell constituents such as MBP (Abou-Donia et al., 2013). Second, a difference in hygienic conditions between the enriched and barren environment may have played a role, even though all pigs were housed in the same room. ...
Article
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Pigs living in commercial husbandry systems may experience both acute stress due to standard management procedures and chronic stress through limitations in their barren housing environment. This might influence their immune status, including antibody responses to neural and danger autoantigens. Levels of natural autoantibody (NAAb)-binding phosphorylcholine-conjugated bovine serum albumin (PC-BSA) and myelin basic protein (MBP) were measured over time in pigs that were kept in environmental enriched v. barren housing, and that underwent a regrouping test. In total, 480 pigs were housed in 80 pens in either barren or straw-enriched pens from 4 through 23 weeks of age. Blood samples were taken from pigs before (week 8), and 3 days after a 24 h regrouping test (week 9), and at 22 weeks of age. Phosphorylcholine-conjugated bovine serum albumin (PC-BSA) and MBP antibody titres in serum were measured using ELISA. Enriched-housed pigs had higher levels of IgM-binding MBP, and tended to have higher levels of IgG-binding MBP and IgA-binding PC-BSA than barren-housed pigs. Each NAAb measured in this study was affected by gender and litter. These results suggest that enriched housing conditions, as well as acute regrouping stress, have an influence on levels of serum NAAb-binding danger and neural antigens in pigs.
... Exposure to ToCP is suspected to occur as a result of bleed air contamination via the aircraft ventilation system; this includes "smoke-in cabin" or smell incidents, involving additives in jet engine oil and their possible oil pyrolysis products (e.g. Abou-Donia et al., 2013;de Boer et al., 2015, and references therein). It is suspected that bleed air contamination incidents from the aircraft ventilation system may contain TCP. ...
... The daily intake over 8 h, based on the four aircraft studies, assuming a constant concentration and 100% uptake by inhalation, ranges from 3 μg (0.4 μg/m 3 ) to 266 μg (38 μg/m 3 ) of TCPs, which is thus above the lowest test concentration. One study investigated auto-antibodies in serum as biomarkers, but its clinical relevance is unclear and it cannot be used for risk assessment (Abou-Donia et al., 2013). Another study concerning induction of acetylcholinesterase and apoptosis in mouse lung cells by a high subcutaneous dose (1500 mg/kg) of ToCP (Jiang et al., 2012) is not relevant for risk assessment of cabin air levels. ...
Article
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Sensory effects in eyes and airways are common symptoms reported by aircraft crew and office workers. Neurological symptoms, such as headache, have also been reported. To assess the commonality and differences in exposures and health symptoms, a literature search of aircraft cabin and office air concentrations of non-reactive volatile organic compounds (VOCs) and ozone-initiated terpene reaction products were compiled and assessed. Data for tricresyl phosphates, in particular tri-ortho-cresyl phosphate (ToCP), were also compiled, as well as information on other risk factors such as low relative humidity.
... Parkinson disease (PD) affects approximately seven million people worldwide, the elderly especially groups aged 50 years and over (El-Metwally et al. 2019). It is a degenerative disorder of the central nervous system resulting from the death of dopamine-generating cells in the substantial nigra in midbrain (Shulman et al. 2011;Abou-Donia et al. 2013). Early symptoms of PD include shaking, rigidity, slowness of movement, and difficulty with walking. ...
Chapter
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A good diet may deliver micronutrients such as vitamins A, B6, B12, C, and D and minerals such as iron, copper, zinc, and selenium that have been implicated to have key roles for supporting immunity with reducing host infections. Most studies have shown that once the subject was infected, the immune system will be enhanced, which will require high levels of metabolic rate, energy requirements, different biosynthesis substances and regulatory molecules, which are obtained from dietary sources. Consequently, a healthy diet will result in a healthy gut by achieving well-balanced gut microbiota which enhances the immune system. The human gut microbiota consists of two major two groups: Firmicutes and Bacteroidetes. Some of these can beneficial, some can be detrimental to the host. Their composition can be modified by small changes in diet when beneficially supports the body’s repair, growth, and immunity. Dietary sources can be converted into beneficial metabolic end-products such as short chain fatty acids, i.e., acetate, propionate, and butyrate, fermented by the beneficial gut microbiota such as Lactobacillus and Bifidobacterium. This is achieved by an indirect nutrient strategy using pro/prebiotic. The gut microbiota cooperates with their hosts for metabolic and nervous systems development, in addition to the function of the immune system regulation via dynamic bidirectional communication known as the gut–brain axis. Indeed, studies have shown a correlation with anxiety, pain, cognition, and mood regulation in animal models studies, related to gut microbiota due to dietary. N. A. Khalil (*) Nutrition and Food Sciences Department, Faculty of Home Economics, Menoufia University, Shibin El Kom, Egypt e-mail: nazih.khalil@hec.menofia.edu.eg S. R. Sarbini Department of Food and Nutritional Sciences, University of Reading, Reading, UK Present Address: Department of Crop Science, Faculty of Agricultural Science and Forestry, Universiti Putra Malaysia Kampus, Bintulu Sarawak, Sarawak, Malaysia e-mail: shahrulrazid@upm.edu.my
... Hageman et al. (2020aHageman et al. ( , 2020b suggest that if an individual were to have a low PON 1 activity and high cytochrome P450 action, they might be up to 4000× more susceptible to OP exposure. Additionally, elevated autoantibodies indicative of CNS damage have been identified in the blood of ill flight crew by Abou-Donia et al. (2013) and Abou-Donia and Brahmajothi (2020). Healthy participants may also display indications of exposure; Carletti et al. (2011) describe an adduct of CBDP and BChE, which may be unique to ToCP exposure; this adduct was identified in half of a group of airline passengers who displayed no health effects (Liyasova et al., 2011). ...
Article
Occupational exposure to oil fumes, organophosphates, halogenated flame retardants, and other volatile and semi-volatile contaminants is a concern within the aviation industry. There is no current consensus on the risk attributed to exposure to these chemical classes within the aircraft cabin. Contaminant concentrations rarely exceed conventional air quality guidelines, but concerns have been raised about these guidelines' applicability within the aircraft environment. This systematic review, the largest and most comprehensive completed to date on the subject matter, aims to synthesize the existing research related to chemical and other exposures inside the aircraft cabin to determine the occupational risk that may be attributed said exposure, as well as, determine knowledge gaps in source, pathway, and receptor that may exist. The Science Direct, Scopus, and Web of Science databases were queried with five search terms generating 138 manuscripts that met acceptance criteria and screening.. Several potential areas requiring future examination were identified: Potable water on aircraft should be examined as a potential source of pollutant exposure, as should air conditioning expansion turbines. Historical exposure should also be more fully explored, and non-targeted analysis could provide valuable information to comprehend the aircraft cabin exposome. Occupational risk under typical flight scenarios appears to be limited for most healthy individuals. Contaminants of concern were demonstrated to be extant within the cabin, however the concentrations under normal circumstances do not appear to be individually responsible for the symptomologies that are present in impacted individuals. Questions remain regarding those that are more vulnerable or susceptible to exposure. Additionally, establishing the effects of chronic low dose exposure and exposure to contaminant mixtures has not been satisfied. The risk of acute exposure in mitigable fume events is substantial, and technological solutions or the replacement of compounds of concern for safer alternatives should be a priority.
... Our previous studies have shown a strong association to neural-specific autoimmune autoantibody as a risk for neuronal injury in aircraft crews. 28,29 Repeated exposures to sublethal doses of organophosphate-related compounds can cause delayed neurotoxicity. As a result, some may exhibit a variety of symptoms. ...
Article
Introduction Military and civil aviation have documented physiological episodes among aircrews. Therefore, continued efforts are being made to improve the internal environment. Studies have shown that exposures to many organic compounds present in emissions are known to cause a variety of physiological symptoms. We hypothesize that these compounds may reversibly inhibit acetylcholinesterase, which may disrupt synaptic signaling. As a result, neural proteins leak through the damaged blood-brain barrier into the blood and in some, elicit an autoimmune response. Materials and Methods Neural-specific autoantibodies of immunoglobulin-G (IgG) class were estimated by the Western blotting technique in the sera of 26 aircrew members and compared with the sera of 19 normal healthy nonaircrew members, used as controls. Results We found significantly elevated levels of circulating IgG-class autoantibodies to neurofilament triplet proteins, tubulin, microtubule-associated tau proteins (Tau), microtubule-associated protein-2, myelin basic protein, and glial fibrillary acidic protein, but not S100 calcium-binding protein B compared to healthy controls. Conclusion Repetitive physiological episodes may initiate cellular injury, leading to neuronal degeneration in selected individuals. Diagnosis and intervention should occur at early postinjury periods. Use of blood-based biomarkers to assess subclinical brain injury would help in both diagnosis and treatment.
... In addition to AChE, OPs can affect hundreds of other enzymes, receptors, and proteins (Costa, 2018) and influence multiple neurobiological processes including inflammation (Koo et al., 2018;Mohammadzadeh et al., 2018), oxidative stress (Eftekhari et al., 2018;Abolaji et al., 2017), autoimmunity (Abou-Donia et al., 2013El Rahman et al., 2018), and axonal transport (Gao et al., 2016(Gao et al., , 2017. Given this level of complexity, it would appear that a multi-target approach to drug discovery would likely have more potential for treating https://doi.org/10.1016/j.tox.2020.152379 ...
Article
Organophosphates (OPs) are valuable as pesticides in agriculture and for controlling deadly vector-borne illnesses; however, they are highly toxic and associated with many deleterious health effects in humans including long-term neurological impairments. Antidotal treatment regimens are available to combat the symptoms of acute OP toxicity, which result from the irreversible inhibition of acetylcholinesterase (AChE). However, there are no established treatments for the long-term neurological consequences of OP exposure. In addition to AChE, OPs can negatively affect multiple protein targets as well as biological processes such as axonal transport. Given the fundamental nature of axonal transport to neuronal health, we rationalized that this process might serve as a general focus area for novel therapeutic strategies against OP toxicity. In the studies described here, we employed a multi-target, phenotypic screening, and drug repurposing strategy for the evaluations of potential novel OP-treatments using a primary neuronal culture model and time-lapse live imaging microscopy. Two multi-target compounds, lithium chloride (LiCl) and methylene blue (MB), which are FDA-approved for other indications, were evaluated for their ability to prevent the negative effects of the OP, diisopropylfluorophosphate (DFP) on axonal transport. The results indicated that both LiCl and MB prevented DFP-induced impairments in anterograde and retrograde axonal transport velocities in a concentration dependent manner. While in vivo studies will be required to confirm our in vitro findings, these experiments support the potential of LiCl and MB as repurposed drugs for the treatment of the long-term neurological deficits associated with OP exposure (currently an unmet medical need).
... Recent studies have measured immunoglobin (IgG) levels using Western blotting against neurofilament triplet proteins (NFP), tubulin, microtubule-associated tau proteins, microtubule-associated protein-2 (MAP-2), myelin basic protein (MBP), glial fibrillary acidic protein (GFAP), and glial S100B protein [6,10] and find evidence of central nervous system (CNS) injury. For example, 34 flight crew with CNS related complaints, were found to have higher auto-antibody-levels than matched controls [6], but again, causation cannot be determined. ...
Article
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Introduction: The term aerotoxic syndrome (ATS) was proposed 20 years ago to describe a constellation of symptoms reported by pilots and cabin crew following exposure to hydraulic fluids, engine oil, and pyrolysis products during flight. Hydraulic fluids and engine oil contain a large number of potentially toxic chemicals, including various organophosphate compounds (OPCs). However, ATS is not yet recognised as a valid diagnosis in aviation or general medicine, because the incidence and aetiology continues to be debated. Discussion: Early studies report findings from symptom surveys or cognitive assessments of small samples of self-selected aircrew, but objective measures of exposure were lacking. Over the last decade, researchers have used more sophisticated techniques to measure exposure, such as on board monitoring studies and biomarkers of exposure (e.g., reduced levels of serum butyrylcholinesterases [BChE]) and more sophisticated techniques to detect nervous system injuries such as fMRI and autoantibody testing. Consideration has also been given to inter-individual differences in the ability to metabolise certain chemical compounds as a result of genetic polymorphisms and exclusion of other potential causes of ill health. Conclusions: We discuss factors which suggest a diagnosis of probable ATS; recommend an assessment protocol which incorporates the aforementioned techniques; and propose diagnostic criteria for probable ATS, based on our previously reported findings in aircrew and the results of recent studies.
... Whilst aerotoxic syndrome has not been fully accepted as a 36 medical syndrome ( Wolkoff et al., 2016) it is commonly used to refer to the symptoms resulting from 37 long term and repeated acute exposure of crew and passengers to toxic compounds in aircraft air 38 (Winder and Balouet, 2002). A growing number of studies have shown that aircraft crew develop 39 symptoms consistent with exposure to organophosphates ( Abou-Donia et al., 2013, Harrison and 40 Mackenzie Ross, 2016, Liyasova et al., 2011, Payne, 2015. 41 ...
... In each study, higher levels of autoantibody reactivity against the following proteins were detected in both the veterans with GWI and the pesticide exposed farmers (compared to controls): neurofilament triplet proteins (NFP), tubulin, microtubule associated tau proteins (Tau), microtubule associated protein-2 (MAP-2), myelin basic protein (MBP), myelin associated glycoprotein (MAG), glial fibrillary acidic protein (GFAP), and calcium-calmodulin kinase II (CaMKII). The findings of these two studies were similar to a previous study (Abou-Donia et al., 2013) of flight crewmembers who experienced symptoms now referred to as "Aerotoxic Syndrome" and who reported being exposed to cabin air emissions which may have contained OPs. Collectively, while the Naughton and Terry Page 10 ...
Article
The term organophosphate (OP) refers to a diverse group of chemicals that are found in hundreds of products worldwide. As pesticides, their most common use, OPs are clearly beneficial for agricultural productivity and the control of deadly vector-borne illnesses. However, as a consequence of their widespread use, OPs are now among the most common synthetic chemicals detected in the environment as well as in animal and human tissues. This is an increasing environmental concern because many OPs are highly toxic and both accidental and intentional exposures to OPs resulting in deleterious health effects have been documented for decades. Some of these deleterious health effects include a variety of long-term neurological and psychiatric disturbances including impairments in attention, memory, and other domains of cognition. Moreover, some chronic illnesses that manifest these symptoms such as Gulf War Illness and Aerotoxic Syndrome have (at least in part) been attributed to OP exposure. In addition to acute acetylcholinesterase inhibition, OPs may affect a number of additional targets that lead to oxidative stress, axonal transport deficits, neuroinflammation, and autoimmunity. Some of these targets could be exploited for therapeutic purposes. The purpose of this review is thus to: 1) describe the important uses of organophosphate (OP)-based compounds worldwide, 2) provide an overview of the various risks and toxicology associated with OP exposure, particularly long-term neurologic and psychiatric symptoms, 3) discuss mechanisms of OP toxicity beyond cholinesterase inhibition, 4) review potential therapeutic strategies to reverse the acute toxicity and long term deleterious effects of OPs.
... The results suggest that these OPEs have very different protein binding affinities in comparison to OP insecticides, or they may possess a specific form of currently unknown toxicity ( AbouDonia, 2003;Casida and Quistad, 2004;Schang et al., 2016). For example, ortho-TMPP (also known as tri-ortho-cresyl phosphate (ToCP)) is neurotoxic, and exposure to ToCP has been associated with the alleged Aerotoxic syndrome ( Abou-Donia et al., 2013;de Ree et al., 2014). Most environmentally relevant OPE FRs and OPE plasticizers have shown low persistence and bioaccumulation po- tential in biota as they are rapidly metabolized ( Greaves et al. 2016c). ...
Article
Organophosphorus (OP) compounds can bind covalently to many types of proteins and form protein adducts. These protein adducts can indicate the exposure to and neurotoxicity of OPs. In the present work, we studied adduction of tubulin with the OP insecticide profenofos in vitro and optimized the method for detection of adducted peptides. Porcine tubulin was incubated with profenofos and was then digested with trypsin, followed by mass spectrometric identification of the profenofos-modified tubulin and binding sites. With solvent-assisted digestion (80% acetonitrile in digestion solution), the protein was digested for peptide identification, especially for some peptides with low mass. The MALDI-TOF-MS and LC-ESI-TOF-MS analysis results showed that profenofos bound covalently to Tyr83 in porcine α-tubulin (TGTY*83R) and to Tyr281 in porcine β-tubulin (GSQQY*281R) with a mass increase of 166.02 Da from the original peptide fragments of porcine tubulin proteins. Tyrosine adduct sites were also confirmed by MALDI-TOF/TOF-MS analysis. This result may partially explain the neurotoxicity of profenofos at low doses and prolonged periods of exposure.
... PC is a component of cell membranes and levels of anti-PC antibodies may reflect cell damage and inflammation related to stress [14]. MBP is an important protein in the nervous system, and levels of antibodies binding MBP were affected by mental stress [15]. Furthermore, Reimert et al. [16] reported that enriched housed pigs had higher levels of natural antibodies (NAb) binding keyhole limpet hemocyanin (KLH) than barren housed pigs. ...
Article
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Housing of pigs in barren, stimulus-poor housing conditions may influence their immune status, including antibody responses to (auto-)antigens, and thus affect immune protection, which will influence the onset and outcome of infection. In the present study, we investigated the effects of environmental enrichment versus barren housing on the level of natural (auto-)antibodies (NA(A)b) and their isotypes (IgM and IgG) binding keyhole limpet hemocyanin (KLH), myelin basic protein (MBP), and phosphorycholine conjugated to bovine serum albumin (PC-BSA) in pigs co-infected with porcine reproductive and respiratory syndrome virus (PRRSV) and Actinobacillus pleuropneumoniae (A. pleuropneumoniae). Pigs (n = 56) were housed in either barren or enriched pens from birth to 54 days of age. They were infected with PRRSV on 44 days of age, and with A. pleuropneumoniae 8 days later. Blood samples were taken on 7 different sampling days. Housing significantly affected the overall serum levels of NA(A)b binding KLH, MBP and PC-BSA, and before infection barren housed pigs had significantly higher levels of NA(A)b than enriched housed pigs, except for KLH-IgM and PC-BSA-IgG. Infection only affected the IgM, but not the IgG isotype. Moreover, changes in MBP-IgM and PC-BSA-IgM following infection were different for enriched and barren housed pigs. These results suggest that the effect of infection on NA(A)b is influenced by housing conditions and that NA(A)b, especially IgM may be affected by infection.
... Autoimmunity (and autoantibodies) may also play a major role in Alzheimer's and Parkinson's disease ( Neff et al., 2008). Increased levels of autoantibodies to neural proteins have been seen in a number of populations exposed to toxic agents such as molds and mycotoxins ( Campbell et al., 2003;Gray et al., 2003), airplane flight crews exposed to hydraulic fluids ( Abou-Donia et al., 2013a), solvent-contaminated domestic water supplies ( Byers et al., 1988), pesticides ( Thrasher et al., 1993;El Rahman et al. 2017), arsenic ( AbouDonia et al., 2013b) gold miners exposed to mercury and other heavy metals ( Gardner et al., 2010), polychlorinated biphenyls, and perfluorinated compounds in children consuming a high fish diet ( Osuna et al., 2014). A recent study reported that neural autoantibodies were significantly higher (except for S-100B) in a group of 20 veterans with Gulf War syndrome patients (mean age 46 years) as compared to 10 controls with low back pain (mean age 50 years) ( Abou-Donia et al., 2017). ...
Article
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A number of studies have linked exposures to industrial and household chemicals and biological toxins to increased risk of autoimmunity in general and elevated levels of autoantibodies to neural antigens specifically. Elevated neural autoantibodies are biomarkers for many diseases such as multiple sclerosis and Parkinson’s disease. Our study reports levels of six types of neural autoantibodies in a group of 24 toxicant-exposed patients. The patients were exposed to a variety of toxicants including contaminated drinking water (four patients), building water/mold damage (eight patients), pesticides (four patients), and other assorted toxic chemicals (eight patients). Levels of all six neural autoantibodies were significantly elevated in most patients and in the patient group at large, with mean antibody levels for the 24 chemically exposed patients (relative to a healthy control population), in descending order: 475% for tau proteins, 391% for microtubule associated proteins-2, 334% for neurofilament proteins (NFP), 302% for myelin basic protein, 299% for glial fibrillary acidic proteins, and 225% for tubulin. Tau protein autoantibodies were significantly elevated in the patient groups with peripheral neuropathy, muscle and joint pain, asthma, and chemical sensitivity. Autoantibodies to tubulin were significantly higher in the chemical sensitivity and asthma patients, autoantibodies to NFP were significantly higher in the patients with sleep apnea, whereas S-100B autoantibodies were significantly increased in patients with muscle/joint pain, asthma, and apnea/insomnia. In patients exposed to environmental toxicants, measurements of autoantibodies may be useful for prevention, diagnosis, and treatment. This study adds to the scientific literature the ability of a broad spectrum of environmental triggers adversely affecting the nervous system through the process of autoimmunity, which may explain the increasing incidence of neurodegenerative diseases.
... Oxidative stress was found to act as a contributor to chronic OPinduced neurotoxicity through inhibition of oxidative biomarkers including superoxide dismutase, glutathione reductase, glutathione-S-transferase, catalase, and glutathione peroxidase (Ali 2012). Another study found an association between exposures of flight crew members to OP pesticides and autoantibodies against glial and neuronal proteins that result from brain injury (Abou-Donia et al. 2013;Heutelbeck et al. 2016). Evidence indicates the need for more investigations to identify other mechanisms of deterioration in NB performance as a result of chronic exposure to OP pesticides (Burns et al. 2013;Li et al. 2012). ...
Article
Egyptian adolescents are hired as seasonal workers to apply pesticides to the cotton crop and may perform this occupation for several years. However, few studies examined the effects of repeated pesticide exposure on health outcomes The goal of this study was to determine the impact of repeated pesticide exposure on neurobehavioral (NB) performance and biomarkers of exposure (urinary metabolite) and effect (cholinesterase activity). Eighty-four adolescents from two field stations in Menoufia, Egypt, were examined four times: before and during pesticide application season in 2010 and again before and during application season in 2011. At each of the four time points, participants completed a questionnaire, performed an NB test battery, and were assessed for urinary levels of the chlorpyrifos metabolite TCPy (3,5,6-trichloro-2-pyridinol) and blood cholinesterase activity. Following the study cohort over two consecutive pesticide application seasons revealed that TCPy levels significantly increased following exposure, and returned to baseline levels following the end of the application season. Blood butyryl cholinesterase activity exhibited a similar pattern. Although NB outcomes displayed learning and practice effects over time, deficits in performance were significantly associated with increased TCPy levels with reduction in the number of NB measures showing improvement over time. Biomarkers of exposure and effect demonstrated changes associated with pesticide application and recovery after application ended. Deficits in NB performance were correlated with elevated pesticide exposure. Data demonstrated that repeated pesticide exposure may exert a long-term adverse impact on human health.
... The CNS symptoms, which include diminished short-term memory, poor attention/concentration, chronic headaches, fatigue, and impaired sleep, are consistent with chronic exposure to neurotoxicants including organophosphate (OP) pesticides and nerve agents. [2][3][4] Gulf War (GW) veterans were exposed to toxicants including OP pesticides, pyridostigmine bromide (PB) anti-nerve gas pills, and low-level sarin nerve agents. 1,5 However, a mechanistic explanation for the association of these toxicants to GWI remains undetermined, and there are no current treatments that have substantially improved cognitive functioning or other chronic health problems of veterans with GWI. ...
Article
Full-text available
Gulf War illness (GWI), which afflicts at least 25% of veterans who served in the 1990–1991 war in the Persian Gulf, is thought to be caused by deployment exposures to various neurotoxicants, including pesticides, anti–nerve gas pills, and low-level nerve agents including sarin/cyclosarin. GWI is a multisymptom disorder characterized by fatigue, joint pain, cognitive problems, and gastrointestinal complaints. The most prominent symptoms of GWI (memory problems, poor attention/concentration, chronic headaches, mood alterations, and impaired sleep) suggest that the disease primarily affects the CNS. Development of urgently needed treatments depends on experimental models appropriate for testing mechanistic hypotheses and for screening therapeutic compounds. Rodent models have been useful thus far, but are limited by their inability to assess the contribution of genetic or epigenetic background to the disease, and because disease-vulnerable proteins and pathways may be different in humans relative to rod
... The results suggest that these OPEs have very different protein binding affinities in comparison to OP insecticides, or they may possess a specific form of currently unknown toxicity (Abou-Donia 2003; Casida and Quistad 2004;Schang et al. 2016). For example, ortho-TMPP (also known as tri-ortho-cresyl phosphate (ToCP)) is neurotoxic, and exposure to ToCP has been associated with the alleged Aerotoxic syndrome (Abou-Donia et al. 2013, de Ree et al. 2014. Most environmentally relevant OPE FRs and OPE plasticizers have shown low persistence and bioaccumulation potential in biota as they are rapidly metabolized (Greaves et al. 2016c). ...
Article
Full-text available
Organophosphate (OP) and organophosphate ester (OPE) adducts of albumin are valuable biomarkers for retrospective verification of exposure. In the present study, our goal was to determine whether OPE flame retardants (OPE FRs) and OPE plasticizers can covalently bind to human serum albumin (HSA), which would allow the resulting adducts to be used to evaluate exposure. Eleven OPE FRs and plasticizers were examined in a HSA-adduct in vitro assay. Pure HSA was incubated with the target OPEs, as well as with an OP insecticide (profenofos) positive control. After enzymatic cleavage with pepsin or Glu-C, the digested albumin was analyzed by matrix-assisted laser desorption ionization tandem time-of-flight mass spectrometry (MALDI-TOF/TOF-MS) and liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-Q-ToF-MS). Under optimized HSA assay conditions, tyrosine adducts were formed at Y411 and Y148/Y150 with a characteristic mass shift for phosphorylation (Δm/z 166) for the profenofos positive control. However, no such phosphorylated peptides were detected for the 11 target OPEs. This negative result suggests that these OPEs have very different affinities from the OP insecticide. They are less reactive or they may specifically interact with other proteins.
... This unfiltered air may sometimes be contaminated with hydraulic fluids or synthetic jet engine oils. Medical record reviews of exposed airline crewmembers showed acute respiratory and/or central nervous system symptoms, again emphasizing the need to learn more about which airborne pollutants affect human health (Abou-Donia, Abou-Donia et al., 2013;Reneman, Schagen et al., 2015). These studies show that a better understanding of when, where and how humans are exposed to airborne pollutions is essential to estimate its possible impact on human health. ...
Article
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The United Nations have projected the world population to reach 9.6 billion by 2050 and that, by then, over 50% of the world population will be living in urban areas. This continuing population growth and accompanying urbanization lead to serious concerns about clean water and food for all, but also about climate change and pollution. Soil and water pollution are directly affecting the crops grown for consumption, and air pollution is affecting our mucosal barriers in the respiratory and gastro-intestinal tract on a daily basis. This review provides an overview of the different types of pollution, and the health effects triggered by especially air pollution ranging from heart disease, pulmonary disease, cancer, to fatal respiratory infections. In addition, the differences in how pollution-induced effects are affecting different age-groups are discussed. Finally, the socio-economic causes and consequences (e.g. Quality of Life and Years of Life Losses versus medical care cost) of these pollution-induced diseases are debated.
... Thus, not the tri-ortho-cresyl phosphate per se exerts the toxic action but its metabolite, the 2-(ortho-cresyl)-4H-1,2,3-benzodioxaphosphoran-2-one which different greatly with P450 1A2 and 3A4 phenotypes. The health hazardous of exposure of aircrew team to organophosphate whose sources were flames retardants and engine leaks was studied using by using the following auto antibodies against seven proteins that are associated with neurodegeneration, microtubule-associated tau proteins, tubulin, neurofilament triplet proteins, microtubule-associated protein-2, glial fibrillary acidic protein (GFAP), myelin basic protein and glial S100B protein (Donia et al., 2013 ). Western blotting was used to detect the Immunoglobulin G (IgG) in 34 aircrew team and 12 controlled healthy individuals . ...
Article
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Organophosphorus flame retardants (OPFRs) are used as additives in plasticizers, foams, hydraulic fluids, anti-foam agents, and coatings for electronic components/devices to inhibit flames. These chemicals were developed and used as flame retardants because of environmental and health concerns of previously used brominated and chlorinated flame retardants (FRs). OPCFRs are divided into five main groups: organophosphates, organophosphonates, organophosphinates, organoposphine oxide, and organophosphites. Most of OPFRs are organophosphate esters that are further classified into the following five groups: 1. Aliphatic, 2. Brominated aliphatic, 3. Chlorinated aliphatic, 4. Aromatic-aliphatic, and 5. Aromatic phosphates. These OPFRs have the following neurotoxic actions: 1. Cholinergic Neurotoxicity, 2. Organophosphate-Induced Delayed Neurotoxicity (OPIDN), and 3. Organophosphate-Induced Chronic Neurotoxicity (OPICN) in addition to being endocrine disruptors. OPFRs have very low cholinergic neurotoxicity and this effect does not pose significant health hazards to adults or children. On the other hand, some OPFRs have shown to cause OPIDN that is a delayed central-peripheral axonopathy, characterized by neuronal cell death of the lower brain regions, spinal cord and peripheral nervous systems, leading to long-term neuronal injury. OPICN is characterized by neuronal cell death in the cortex, hippocampus campus and cerebellum and spinal cord. Finally, OPCFRs act as endocrine disrupters, that affect many functions of the body such thyroid glands and reproductive functions, and may be involved in the development of diabetes and cancer. Residues of these OPCFRs are widespread in the environment, home and workplaces. These chemicals adversely affect human health, especially for vulnerable population such as the elderly, pregnant women, fetuses, and children. Because some OPFRs cause neuronal cell death in the brain and spinal cord that do not repair as well as act as endocrine disrupters they may lead to permanent functional deficits such obesity, memory impairment, decreased motor skill and even more serious diseases such as diabetes and cancer. Because recent reports have accredited FRs for significant decrease in building fires, it is important to balance the risk and benefits of FRs and to use only the safest available FRs including OPFRs.
... Human occupational exposure to ToCP, for example via contaminated cabin air in aircraft, has received particular attention as it has been proposed to result in neurological complaints such as the so-called aerotoxic syndrome (Winder et al., 2002;Ross, 2008;Furlong, 2011;Liyasova et al., 2011;Abou-Donia et al., 2013). As a consequence of its neurotoxicity and the proposed association with aerotoxic syndrome, the commercial use of ToCP has been strongly reduced over the last decades and ToCP now constitutes no more than 2% of the commercial TCP blends used in aircraft engine oil (SAE, 2005;DeNola et al., 2008, Table 1). ...
Article
Exposure to tricresyl phosphates (TCPs), via for example contaminated cabin air, has been associated with health effects including the so-called aerotoxic syndrome. While TCP neurotoxicity is mainly attributed to ortho-isomers like tri-ortho-cresyl phosphate (ToCP), recent exposure and risk assessments indicate that ToCP levels in cabin air are very low. However, the neurotoxic potential of non-ortho TCP isomers and TCP mixtures is largely unknown. We therefore measured effects of exposure (up to 48 h) to different TCP isomers, mixtures and the metabolite of ToCP (CBDP: cresyl saligenin phosphate) on cell viability and mitochondrial activity, spontaneous neuronal electrical activity, and neurite outgrowth in primary rat cortical neurons.
... Additionally, Abou-Donia et al. (2013) have suggested that measurement of serum auto-antibody levels might be useful in terms of demonstrating nervous system damage following exposure to engine oil fumes. They detected increased levels of various auto-antibodies which are released into the blood stream following damage to the central nervous system (e.g., IgG, NFP, tubulin, tau proteins, MAP-2, MBP, S100B protein and GFAP) in 34 aircrew who experienced adverse health effects after being exposed to engine oil fumes. ...
Article
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Toxicology is a new science, the complexities of which have been highlighted in the papers contained within this special section. Our understanding of the mechanisms through which various chemicals interfere with nervous system function is constantly evolving and research is unable to keep up with the speed with which new chemicals are produced and put onto the market. Thus there are often controversies surrounding the health-effects of commercially available compounds and disagreement around what constitutes safe exposure limits. This article will introduce readers to an emerging concern in this field, the potential risk to health of toxic fumes in airplane cabins. We explore the challenges and methodological issues encountered by researchers who have tried to investigate this issue and highlight the need for further research on this topic. We hope this article will promote discussion amongst academics and clinicians, and lead to the identification of creative solutions to the methodological issues encountered to date.
... Autoantibodies have been detected in the blood following damage to tissues in the periphery, such as damage to heart tissue following intraoperative myocardial ischemia (Bledzhyants et al., 2007) and liver damage during hepatitis B infection (McFarlane et al., 1995). Furthermore, autoantibodies have been detected in the peripheral blood after damage to brain tissue including following stroke (Bornstein et al., 2001), head trauma (Marchi et al., 2013), and neurodegenerative diseases (Diamond et al., 2013), as well as following exposure to neurotoxic chemicals (Abou-Donia et al., 2013;El-Fawal et al., 1996;El-Fawal and McCain, 2008;El-Fawal and O'Callaghan, 2008). These findings suggest that autoantibodies may be used as surrogate measures of the occurrence (state), and possibly the severity (stage), of tissue damage from chemical exposure. ...
Article
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Methylmercury, polychlorinated biphenyls (PCBs), and perfluorinated compounds (PFCs) are ubiquitous and persistent environmental chemicals with known or suspected toxic effects on the nervous system and the immune system. Animal studies have shown that tissue damage can elicit production of autoantibodies. However, it is not known if autoantibodies similarly will be generated and detectable in humans following toxicant exposures. Therefore, we conducted a pilot study to investigate if autoantibodies specific for neural and non-neural antigens could be detected in children at age 7 years who have been exposed to environmental chemicals. Both prenatal and age-7 exposures to mercury, PCBs, and PFCs were measured in 38 children in the Faroe Islands who were exposed to widely different levels of these chemicals due to their seafood-based diet. Concentrations of IgM and IgG autoantibodies specific to both neural (neurofilaments, cholineacetyltransferase, astrocyte glial fibrillary acidic protein, and myelin basic protein) and non-neural (actin, desmin, and keratin) antigens were measured and the associations of these autoantibody concentrations with chemical exposures were assessed using linear regression. Age-7-blood mercury concentrations were positively associated with titers of multiple neural- and non-neural-specific antibodies, mostly of the IgM isotype. Additionally, prenatal blood-mercury and -PCBs were negatively associated with anti-keratin IgG and prenatal PFOS was negatively associated with anti-actin IgG. These exploratory findings demonstrate that autoantibodies can be detected in the peripheral blood following exposure to environmental chemicals. The unexpected association of exposures with antibodies specific for non-neural antigens suggests that these chemicals may have toxicities that have not yet been recognized.
... We have previously published result of NAb utility in OPIDP induced by phenyl saligenin phosphate (PSP) and amelioration with calcium channel blockade in the hen, the Environmental Protection Agency's (EPA) mandated model [23]. These results have been confirmed in humans by AbouDonia and colleagues [25]. ...
Article
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The majority of neurodegenerative (ND) and autoimmune diseases (AID) remain idiopathic. The contribution of environmental chemicals to the development of these disorders has become of great interest in recent years. A convergence of mechanism between of ND and AID development has also emerged. In the case of ND, including neurotoxicity, the focus of this review, work over the last two decade in the realm of biomarker development, indicates that the immune response provides a venue whereby humoral immunity, in the form of autoantibodies to nervous system specific proteins, or neuroantibodies (NAb), may provide, once validated, a sensitive high throughput surrogate biomarker of effect with the potential of predicting outcome in absence of overt neurotoxicity/neurodegeneration. In addition, NAb may prove to be a contributor to the progression of the nervous system pathology, as well as biomarker of stage and therapeutic efficacy. There is a compelling need for biomarkers of effect in light of the introduction of new chemicals, such as nanoengineered material, where potential neurotoxicity remains to be defined. Furthermore, the convergence of mechanisms associated with ND and AID draws attention to the neglected arena of angiogenesis in defining the link between environment, ND, and AID.
... Autoantibodies against neuron-specific proteins have been previously detected in peripheral blood. [26][27][28][29][30] Our western blot analysis showed high molecular weight (MW) NfH-stained bands (possible aggregates) in plasma from patients with ALS (second lane from the left side of panel; figure 4), partially dissociated into lower MW fragments by urea incubation (fourth lane from the left side of panel; figure 4), as previously shown in SOD1 G93A mice that model ALS. 24 No high MW aggregates or low MW fragments were observed in purified bNfH (the first and third lanes from the left side of panel, figure 4) as previously shown. ...
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Objective To investigate the role of longitudinal plasma neurofilament heavy chain protein (NfH) levels as an indicator of clinical progression and survival in amyotrophic lateral sclerosis (ALS). Methods A cross-sectional study involving 136 clinically heterogeneous patients with ALS and 104 healthy and neurological controls was extended to include a prospective analysis of 74 of these ALS cases, with samplings at approximately 3-month intervals in a follow-up period of up to 3 years. We analysed the correlation between longitudinal NfH-phosphoform levels and disease progression. Temporal patterns of NfH changes were evaluated using multilevel linear regression. Results Baseline plasma NfH levels were higher than controls only in patients with ALS with short disease duration to baseline sampling. Compared with controls, fast-progressing patients with ALS, particularly those with a short diagnostic latency and disease duration, had higher plasma NfH levels at an early stage and lower levels closer to end-stage disease. Lower NfH levels between visits were associated with rapid functional deterioration. We also detected antibodies against NfH, NfH aggregates and NfH cleavage products. Conclusions Disease progression in ALS involves defined trajectories of plasma NfH levels, reflecting speed of neurological decline and survival. Intervisit plasma NfH changes are also indicative of disease progression. This study confirms that longitudinal measurements of NfH plasma levels are more informative than cross-sectional studies, where the time of sampling may represent a bias in the interpretation of the results. Autoantibodies against NfH aggregates and NfH cleavage products may explain the variable expression of plasma NfH with disease progression. Trail registration number NIHRID6160.
... Proof of exposure to other organophosphorus chemicals in jet engine oil is already provided by the GC-MSMS results of Schindler et al. who found elevated levels of dibutyl phosphate and diphenyl phosphate in the urine of aircrew and aircraft maintenance technicians [13,31]. Abou-Donia reported increased levels of autoantibodies against nervous system proteins in flight crew [32]. In conclusion, a positive result for the cresyl phosphate adduct on BChE in persons exposed to fumes in the cabin air, would confirm that the fume event occurred, and that some of the chemicals from the jet engines were absorbed. ...
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Aircrew complain of illness following a fume event in aircraft. A chemical in jet engine oil, the neurotoxicant, tri-o-cresyl phosphate, after metabolic activation to cresyl saligenin phosphate, makes a covalent adduct on butyrylcholinesterase (BChE). We developed a mass spectrometry method for detection of the cresyl phosphate adduct on human BChE, as an indicator of exposure. Monoclonal mAb2, whose amino acid sequence is provided, was crosslinked to cyanogen bromide-activated Sepharose 4B and used to immunopurify plasma BChE treated with cresyl saligenin phosphate. BChE was released with acetic acid, digested with pepsin, and analyzed by LC-MSMS on the 5600 Triple TOF mass spectrometer. Peptide FGES198AGAAS with an added mass of 170 Da from cresyl phosphate on serine 198 was detected as parent ion 966.4 Da. When characteristic daughter ions were monitored in the MSMS spectrum the limit of detection was 0.1% cresyl saligenin phosphate inhibited plasma BChE. This corresponds to 2x10(-9) g in 0.5 ml, or 23x10(-15) moles of inhibited BChE in 0.5 ml plasma. In conclusion, a sensitive assay for exposure to tri-o-cresyl phosphate was developed. Laboratories that plan to use this method are cautioned that a positive result gives no proof that tri-o-cresyl phosphate is toxic at low levels.
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Contamination of aircraft cabin air can result from leakage of engine oils and hydraulic fluids into bleed air. This may cause adverse health effects in cabin crews and passengers. To realistically mimic inhalation exposure to aircraft cabin bleed-air contaminants, a mini bleed-air contaminants simulator (Mini-BACS) was constructed and connected to an air-liquid interface (ALI) aerosol exposure system (AES). This unique “Mini-BACS + AES” setup provides steady conditions to perform ALI exposure of the mono- and co-culture lung models to fumes from pyrolysis of aircraft engine oils and hydraulic fluids at respectively 200 °C and 350 °C. Meanwhile, physicochemical characteristics of test atmospheres were continuously monitored during the entire ALI exposure, including chemical composition, particle number concentration (PNC) and particles size distribution (PSD). Additional off-line chemical characterization was also performed for the generated fume. We started with submerged exposure to fumes generated from 4 types of engine oil (Fume A, B, C, and D) and 2 types of hydraulic fluid (Fume E and F). Following submerged exposures, Fume E and F as well as Fume A and B exerted the highest toxicity, which were therefore further tested under ALI exposure conditions. ALI exposures reveal that these selected engine oil (0–100 mg/m³) and hydraulic fluid (0–90 mg/m³) fumes at tested dose-ranges can impair epithelial barrier functions, induce cytotoxicity, produce pro-inflammatory responses, and reduce cell viability. Hydraulic fluid fumes are more toxic than engine oil fumes on the mass concentration basis. This may be related to higher abundance of organophosphates (OPs, ≈2800 µg/m³) and smaller particle size (≈50 nm) of hydraulic fluid fumes. Our results suggest that exposure to engine oil and hydraulic fluid fumes can induce considerable lung toxicity, clearly reflecting the potential health risks of contaminated aircraft cabin air.
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Among the various chemicals that are commonly used as pesticides, organophosphates (OPs), and to a lesser extent, carbamates, are most frequently associated with adverse long-term neurological consequences. OPs and the carbamate, pyridostigmine, used as a prophylactic drug against potential nerve agent attacks, have also been implicated in Gulf War Illness (GWI), which is often characterized by chronic neurological symptoms. While most OP- and carbamate-based pesticides, and pyridostigmine are relatively potent acetylcholinesterase inhibitors (AChEIs), this toxicological mechanism is inadequate to explain their long-term health effects, especially when no signs of acute cholinergic toxicity are exhibited. Our previous work suggests that a potential mechanism of the long-term neurological deficits associated with OPs is impairment of axonal transport (AXT); however, we had not previously evaluated carbamates for this effect. Here we thus evaluated the carbamate, physostigmine (PHY), a highly potent AChEI, on AXT using an in vitro neuronal live imaging assay that we have previously found to be very sensitive to OP-related deficits in AXT. We first evaluated the OP, diisopropylfluorophosphate (DFP) (concentration range 0.001-10.0 µM) as a reference compound that we found previously to impair AXT and subsequently evaluated PHY (concentration range 0.01-100 nM). As expected, DFP impaired AXT in a concentration-dependent manner, replicating our previously published results. In contrast, none of the concentrations of PHY (including concentrations well above the threshold for impairing AChE) impaired AXT. These data suggest that the long-term neurological deficits associated with some carbamates are not likely due to acute impairments of AXT.
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For the past 30 years, there has been a lack of objective tools for diagnosing Gulf War Illness (GWI), which is largely characterized by central nervous system (CNS) symptoms emerging from 1991 Gulf War (GW) veterans. In a recent preliminary study, we reported the presence of autoantibodies against CNS proteins in the blood of veterans with GWI, suggesting a potential objective biomarker for the disorder. Now, we report the results of a larger, confirmatory study of these objective biomarkers in 171 veterans with GWI compared to 60 healthy GW veteran controls and 85 symptomatic civilian controls (n = 50 myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and n = 35 irritable bowel syndrome (IBS)). Specifically, we compared plasma markers of CNS autoantibodies for diagnostic characteristics of the four groups (GWI, GW controls, ME/CFS, IBS). For veterans with GWI, the results showed statistically increased levels of nine of the ten autoantibodies against neuronal "tubulin, neurofilament protein (NFP), Microtubule Associated Protein-2 (MAP-2), Microtubule Associated Protein-Tau (Tau), alpha synuclein (α-syn), calcium calmodulin kinase II (CaMKII)" and glial proteins "Glial Fibrillary Acidic Protein (GFAP), Myelin Associated Glycoprotein (MAG), Myelin Basic Protein (MBP), S100B" compared to healthy GW controls as well as civilians with ME/CFS and IBS. Next, we summed all of the means of the CNS autoantibodies for each group into a new index score called the Neurodegeneration Index (NDI). The NDI was calculated for each tested group and showed veterans with GWI had statistically significantly higher NDI values than all three control groups. The present study confirmed the utility of the use of plasma autoantibodies for CNS proteins to distinguish among veterans with GWI and other healthy and symptomatic control groups.
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Traumatic brain injury (TBI) is a leading cause of death and disability in the United States and around the world. The primary injury (acute phase) to the brain destroys or damages the neuronal and glial cells and compromises the tissue and blood–brain barrier (BBB) integrity. The secondary injury is a prolonged phase causing cellular, molecular, and functional deficits. TBI evokes systemic and local inflammatory responses. Immune cells migrate to the brain and gain access to the brain parenchyma due to BBB breakdown. The damaged or destroyed cells, displaced proteins or their metabolites are recognized by the immune cells as autoantigens. The autoantibodies generated may be useful as biomarkers of disease severity. The autoimmunity thus developed has a long-lasting effect on the body and can be directed to the brain causing neurodegenerative disorders or elicit systemic autoimmune disorders. Hypopituitarism is one of the major pathophysiological consequences of TBI autoimmunity.
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Tricresyl phosphates (TCPs), a typical sort of organophosphate flame retardants, has received extensive concerns due to its potential adverse effects. However, limited information is available on the efficient and safe removal methods of TCPs. In this regard, TCPs were tentatively biodegraded with Brevibacillus brevis. A probable degradation pathway was further proposed with the cellular reactions discussed in detail. Experiments showed that B. brevis at 2 g L⁻¹ could degrade 1 mg L⁻¹ tri-m-cresyl phosphate, tri-p-cresyl phosphate, and tri-o-cresyl phosphate by 82.91%, 93.91%, and 53.92%, respectively, within five days. In the process of biodegradation, B. brevis metabolism caused the release of Na⁺ and Cl⁻ as well as the absorption of some nutrient ions including K⁺, PO4³⁻, Mg²⁺, and SO4²⁻; the presence of oxalic acid, citric acid, acetic acid, and malonic acid was also detected. Similar metabolic pathways were found among different TCPs isomers, but tri-o-cresyl phosphate induced more reactive oxygen species than the other two did. This work develops novel insights into the potential mechanisms of TCPs biodegradation by microorganisms.
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1991 Gulf War (GW) veterans continue to experience debilitating cognitive and mood problems more than two decades following their return from deployment. Suspected causes for these cognitive complaints include additive and/or synergistic effects of the varying combinations of exposures to chemicals in theater, including pesticides and pyridostigmine bromide (PB) pills. This study was undertaken to address one of the key recommendations of the US Department of Defense Environmental Exposure Report on Pesticides, which was to conduct an epidemiological study to further evaluate the role of neurotoxicant exposures in the expression of central nervous system symptoms reported by GW veterans. This study evaluated the role of pesticides and/or PB in the development of chronic neuropsychological dysfunction in GW veterans. We examined the associations between self-reported measures of pesticide and PB exposures and performance on neuropsychological tests in a group of 159 GW-deployed preventative medicine personnel who had varying levels of pesticide exposures during their work as pesticide applicators or other preventative medicine roles. These veterans had a unique knowledge of pesticides and their usage during the war. It was hypothesized that pesticide applicator personnel with higher exposures would perform significantly worse on objective cognitive measures than lower-exposed personnel and that multiple chemical exposures (pesticide and PB) would further diminish cognitive functioning and increase mood complaints. Study results showed that the participants with both high pesticide and high PB exposure performed worse on specific measures than the groups with high single exposures or low exposures to both toxicants. High combined exposure was associated with significantly slower information processing reaction times, attentional errors, worse visual memory functioning, and increased mood complaints. In addition, stepwise regression analyses of individual pesticide exposures found that pest strip exposure was associated with slower reaction times and attentional errors, and that fly bait and delouser exposures predicted greater mood complaints.
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Gulf War illness (GWI) is primarily diagnosed by symptom report; objective biomarkers are needed that distinguish those with GWI. Prior chemical exposures during deployment have been associated in epidemiologic studies with altered central nervous system functioning in veterans with GWI. Previous studies from our group have demonstrated the presence of autoantibodies to essential neuronal and glial proteins in patients with brain injury and autoantibodies have been identified as candidate objective markers that may distinguish GWI. Here, we screened the serum of 20 veterans with GWI and 10 non-veteran symptomatic (low back pain) controls for the presence of such autoantibodies using Western blot analysis against the following proteins: neurofilament triplet proteins (NFP), tubulin, microtubule associated tau proteins (Tau), microtubule associated protein-2 (MAP-2), myelin basic protein (MBP), myelin associated glycoprotein (MAG), glial fibrillary acidic protein (GFAP), calcium-calmodulin kinase II (CaMKII) and glial S-100B protein. Serum reactivity was measured as arbitrary chemiluminescence units. As a group, veterans with GWI had statistically significantly higher levels of autoantibody reactivity in all proteins examined except S-100B. Fold increase of the cases relative to controls in descending order were: CaMKII 9.27, GFAP 6.60, Tau 4.83, Tubulin 4.41, MAG 3.60, MBP 2.50, NFP 2.45, MAP-2 2.30, S-100B 1.03. These results confirm the continuing presence of neuronal injury/gliosis in these veterans and are in agreement with the recent reports indicating that 25 years after the war, the health of veterans with GWI is not improving and may be getting worse. Such serum autoantibodies may prove useful as biomarkers of GWI, upon validation of the findings using larger cohorts.
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In modern aviation, so-called fume events such as exposure to an unknown mixture of chemicals introduced into the aircraft cabin with bleed air drawn off at the engines may occur. Human exposure may result in (neuro)toxic symptoms described as so-called “aerotoxic syndrome.” Currently, among other agents organophosphates (OP) are regarded as a likely cause of the observed adverse effects. After fume events 11 flight crew members (9 female/2 male; ages 23–58 yr) were admitted for a medical examination within 5 d post exposure. Individual acetylcholinesterase (AChE) and neuropathy target esterase (NTE) activities were determined. Anamnesis and clinical findings confirmed prominent symptoms of an intoxication, including headache, cognitive difficulties, and neurological disorders, among others. Patient AChE activities ranged from 37 to 50 U/g hemoglobin (reference values: 26.7–50.9 U/g hemoglobin). Ten individuals showed NTE activities ranging from 3.14 to 6.3 nmol phenyl valerate/(min × mg protein) (reference values: 3.01–24), with one patient exhibiting low NTE activity of 1.4. Biochemical effect monitoring was applied to encompass a broad range of AChE-inhibiting compounds such as OP, carbamates, and isocyanates, or to detect inhibition of NTE. The measured AChE activities indicated a subordinate contribution of OP or related compounds to the observed symptoms. All noted NTE activities were clustered at low levels. Our data suggest a likely inhibition of NTE activities in patients after fume events, which warrants further investigation. The observed symptoms may be linked to known chemical compounds in fume events, and it is not possible to infer a direct correlation between manifestations and AChE -inhibiting compounds at this time.
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Toxicology is the science that deals with the action of toxicants on human health and the environment. During the twentieth century, toxicology became recognized as a discrete science, with toxicology departments or programs established in many universities around the country. Also, during the past century, two certifications have been established to certify an individual as a toxicologist. The last century also witnessed several major radiation and chemical exposure disasters that required many toxicological studies to be conducted to determine the cause, treatment and prevention of these accidents. A debate has been raging in regard of toxicity testing that resulted in a report on entitled Toxicity Testing in the 21st Century: A Vision and Strategy that was prepared by the US National Research Council in 2007, after being asked by the US Environmental Agency (US EPA) to develop, improve and validate new laboratory tools that could be used to effect a significant improvement in society's ability to understand the hazards and risks posed by chemicals. This report has resulted in useful discussions about better ways of performing toxicity testing.
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Autism is a brain developmental disorder with characteristics of social interaction defects, language and communication dysfunction, and repetitive behavior. Occurrence of autism is continuously increasing, but the cause of autism is not clearly defined. Genetic linkage or environmental factors were proposed as sources for pathogenesis of autism. BTBR T+tf/J (BTBR) mice were reported as an appropriate animal model for autism investigation because of their similarities in behavioral abnormalities with human autistic subjects. The aim of this study was to evaluate expression levels of proteins involved with brain development at fetal stage of BTBR mice. FVB/NJ mice were used as a control strain because of their social behaviors. Level of fetal brain immunoglobulin (Ig) G deposit was also evaluated. Fetal brains were obtained at d 18 of gestational period. Thirty-one and 27 fetuses were obtained from 3 pregnant BTBR and FVB dams, respectively. The level of glial fibrillary acidic protein expression was significantly lower in fetal brains of BTBR than FVB/NJ mice. Expression of brain-derived neurotrophic factor and myelin basic protein was significantly more upregulated in BTBR than in FVB/NJ mice. No significant difference was obtained for nerve growth factor between the two strains. Levels of IgG isotypes deposited in fetal brain of BTBR mice were significantly higher than in FVB mice except for IgG1. Overall, these results suggest that prenatal alterations in expression of various fetal brain proteins may be implicated in aberrant behavioral characteristics of BTBR mice.
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This descriptive study correlates the presence of serum autoantibodies to five neuronal cytoskeletal proteins with neurologic deficits in subjects exposed to arsenic (As). Arsenic exposure remains a serious problem in many countries producing skin lesions and hair loss. More serious manifestations include: liver and kidney damage, encephalopathy, peripheral neuropathy, gangrene of extremities, and cancer. Bangladesh represents one of the countries where high percentage of population is exposed to As through highly contaminated drinking groundwater. Autoantibodies were determined against the following proteins: neurofilament triplet proteins (NFP), microtubule associated protein-2 (MAP2), and microtubule associated protein tau (tau). Sera were obtained from 14 subjects in the severely affected village of Mianpur, Charghat Thana, Rajshahi. Individuals were further divided into group A with objective complaints of organic neurologic damage and group B without neurologic deficits manifestations and eight healthy controls from Rajshahi city. High levels of autoantibodies were detected in five subjects against low molecular weight neurofilaments (NFL) and in two subjects against high molecular weight neurofilament (NFH). Two subjects displayed significantly increased levels of MAP-2 autoantibodies and two others high levels of tau autoantibodies. All elevated autoantibodies were detected in group A subjects who were diagnosed with neurological disorders ranging from sleep disorders to paralysis. The results demonstrate a good correlation between neurologic defects in As-exposed subjects and presence of sera neuronal autoantibodies to cytoskeletal proteins.
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The concerns that were brought to the Australian Federation of Air Pilots regarding air quality problems revealed a number of operational and OHS issues. This prompted the design and conduct of a survey of symptoms in members who fly BAe 146 aircraft in Australia. A total of 19 pilots and two flight attendants responded. Survey respondents showed high rates of symptoms which included headaches, eye, skin and upper airway irritation, neuropsychological impairment, respiratory problems, food/alcohol intolerances, muscle/joint pain, diarrhoea, and so on. While the results of this survey cannot be considered representative, they do provide self-reported data from a small number of pilots about health problems on the BAe 146, and suggest that the denials by the airlines should be re-examined.
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The term "aerotoxic syndrome" was proposed in 1999 to describe the association of symptoms observed among flight crew and cabin crew who have been exposed to hydraulic fluid or engine oil vapours or mists. A descriptive epidemiological study was conducted to investigate the health effects of aircrew through a questionnaire mail-out. Most of the respondents (88%) reported that symptoms occurred after exposure to engine oil or hydraulic fluid leaks which caused odours and/ or visible contamination in the cabin. Invariably, aircrew directly attributed their symptoms to exposure to in-cabin airborne contaminants. A comparison between 18 respondents from the United States and the 50 Australian respondents shows significant similarities in reported symptoms. There was sufficient commonality in reported symptoms to conclude a symptom basis for aerotoxic syndrome.
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Background. Cabin air on commercial aircraft is sometimes contaminated with hydraulic fluids, synthetic jet engine oils and combusted or pyrolized materials. The incidence of contaminated air events is hard to quantify as commercial aircraft do not have air quality monitoring systems on board. In the UK, around 350 aircrew have advised their union that they may be suffering physical and psychological ill health following exposure to contaminated air. Design. This paper presents a case series of 27 pilots referred for psychological assessment. The general aim of the assessment was to determine whether pilots show evidence of cognitive impairment and whether this relates to exposure history. Materials and method. All pilots underwent neuropsychological and adult mental health assessment, undertaken by 12 examiners, instructed to search for alternative explanations other than exposure to toxic fumes for any symptoms reported. Results. Pilots reported alarming cognitive failures at work such as being unable to retain or confusing numerical information from Air Traffic Control. Nine pilots were excluded from further analysis because they had a medical or psychiatric condition which might otherwise explain these difficulties. In the remaining 18 pilots, language, perceptual skills and general intellectual ability were preserved, but performance on tests of psychomotor speed, attention and executive functioning was below expected levels. Conclusions. The cognitive deficits identified in this cohort of pilots cannot be attributed to factors such as mood disorder or malingering. However, the evidence available in this study does not enable firm conclusions to be drawn regarding a causal link with contaminated air; the cohort of pilots was self‐selected and only crude indices of exposure were available. Further research is warranted given the scientific uncertainty regarding the health effects of inhalation of heated or pyrolized engine oil.
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Predicting the long-term outcome after traumatic brain injury (TBI) is an important component of treatment strategy. Despite dramatically improved emergency management of TBI and apparent clinical recovery, most patients with TBI still may have long-term central nervous system (CNS) impairment. Sixty-three patients with TBI were enrolled into the prospective study. Venous blood samples were taken at admission and every 24 h for a maximum of 6 consecutive days. Serum concentrations of the biomarkers S100B, neuron-specific enolase (NSE), GFAP, NF-H, secretagogin and Hsp70 were quantified immuno-luminometrically or by enzyme-linked immunosorbent assay. The outcome was evaluated 6 months after TBI using the Glasgow Outcome Scale (GOS) in all patients. The S100B levels in patients with worse outcome (GOS 4 or death) were already significantly higher at D0 (p < 0.001; p = 0.002). NSE levels were significantly higher in patients who died or had worse outcomes (p < 0.001; p = 0.003). Patients who had worse outcomes (GOS) or died had higher GFAP values (p < 0.001; p < 0.001), but their dynamics were similar over the same period. NF-H grew significantly faster in patients who had a worse GOS or died (p < 0.001; p = 0.001). Although further prospective study is warranted, these findings suggest that levels of biomarkers correlate with mortality and may be useful as predictors of outcome in children with TBI.
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The aircraft cabin and flight deck ventilation are supplied from partially compressed unfiltered bleed air directly from the engine. Worn or defective engine seals can result in the release of engine oil into the cabin air supply. Aircrew and passengers have complained of illness following such "fume events". Adverse health effects are hypothesized to result from exposure to tricresyl phosphate mixed esters, a chemical added to jet engine oil and hydraulic fluid for its anti-wear properties. Our goal was to develop a laboratory test for exposure to tricresyl phosphate. The assay was based on the fact that the active-site serine of butyrylcholinesterase reacts with the active metabolite of tri-o-cresyl phosphate, cresyl saligenin phosphate, to make a stable phosphorylated adduct with an added mass of 80 Da. No other organophosphorus agent makes this adduct in vivo on butyrylcholinesterase. Blood samples from jet airplane passengers were obtained 24-48 h after completing a flight. Butyrylcholinesterase was partially purified from 25 ml serum or plasma, digested with pepsin, enriched for phosphorylated peptides by binding to titanium oxide, and analyzed by mass spectrometry. Of 12 jet airplane passengers tested, 6 were positive for exposure to tri-o-cresyl phosphate that is, they had detectable amounts of the phosphorylated peptide FGEpSAGAAS. The level of exposure was very low. No more than 0.05 to 3% of plasma butyrylcholinesterase was modified. None of the subjects had toxic symptoms. Four of the positive subjects were retested 3 to 7 months following their last airplane trip and were found to be negative for phosphorylated butyrylcholinesterase. In conclusion, this is the first report of an assay that detects exposure to tri-o-cresyl phosphate in jet airplane travelers.
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Aerotoxic syndrome is assumed to be caused by exposure to tricresyl phosphate (TCP), an antiwear additive in jet engine lubricants and hydraulic fluid. CBDP (2-(ortho-cresyl)-4H-1,2,3-benzodioxaphosphoran-2-one) is the toxic metabolite of triortho-cresylphosphate, a component of TCP. Human butyrylcholinesterase (BChE; EC 3.1.1.8) and human acetylcholinesterase (AChE; EC 3.1.1.7) are irreversibly inhibited by CBDP. The bimolecular rate constants of inhibition (k(i)), determined under pseudo-first-order conditions, displayed a biphasic time course of inhibition with k(i) of 1.6 × 10(8) M(-1) min(-1) and 2.7 × 10(7) M(-1) min(-1) for E and E' forms of BChE. The inhibition constants for AChE were 1 to 2 orders of magnitude slower than those for BChE. CBDP-phosphorylated cholinesterases are nonreactivatable due to ultra fast aging. Mass spectrometry analysis showed an initial BChE adduct with an added mass of 170 Da from cresylphosphate, followed by dealkylation to a structure with an added mass of 80 Da. Mass spectrometry in (18)O-water showed that (18)O was incorporated only during the final aging step to form phospho-serine as the final aged BChE adduct. The crystal structure of CBDP-inhibited BChE confirmed that the phosphate adduct is the ultimate aging product. CBDP is the first organophosphorus agent that leads to a fully dealkylated phospho-serine BChE adduct.
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Susceptibility to most autoimmune diseases is dependent on polygenic inheritance, environmental factors, and poorly defined stochastic events. One of the significant challenges facing autoimmune disease research is in identifying the specific events that trigger loss of tolerance and autoimmunity. Although many intrinsic factors, including age, sex, and genetics, contribute to autoimmunity, extrinsic factors such as drugs, chemicals, microbes, or other environmental factors can also act as important initiators. This review explores how certain extrinsic factors, namely, drugs and chemicals, can promote the development of autoimmunity, focusing on a few better characterized agents that, in most instances, have been shown to produce autoimmune manifestations in human populations. Mechanisms of autoimmune disease induction are discussed in terms of research obtained using specific animal models. Although a number of different pathways have been delineated for drug/chemical-induced autoimmunity, some similarities do exist, and a working model is proposed.
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This review summarizes protein biomarkers in mild and severe traumatic brain injury in adults and children and presents a strategy for conducting rationally designed clinical studies on biomarkers in head trauma. We performed an electronic search of the National Library of Medicine's MEDLINE and Biomedical Library of University of Pennsylvania database in March 2008 using a search heading of traumatic head injury and protein biomarkers. The search was focused especially on protein degradation products (spectrin breakdown product, c-tau, amyloid-beta(1-42)) in the last 10 years, but recent data on "classical" markers (S-100B, neuron-specific enolase, etc.) were also examined. We identified 85 articles focusing on clinical use of biomarkers; 58 articles were prospective cohort studies with injury and/or outcome assessment. We conclude that only S-100B in severe traumatic brain injury has consistently demonstrated the ability to predict injury and outcome in adults. The number of studies with protein degradation products is insufficient especially in the pediatric care. Cohort studies with well-defined end points and further neuroproteomic search for biomarkers in mild injury should be triggered. After critically reviewing the study designs, we found that large homogenous patient populations, consistent injury, and outcome measures prospectively determined cutoff values, and a combined use of different predictors should be considered in future studies.
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Organophosphorus ester-induced delayed neurotoxicity (OPIDN) is a neurodegenerative disorder characterized by ataxia progressing to paralysis with a concomitant central and peripheral distal axonapathy. Diisopropylphosphorofluoridate (DFP) produces OPIDN in the chicken, which results in mild ataxia in 7–14 days and severe paralysis as the disease progresses with a single dose. White leghorn layer hens were treated with DFP (1.7 mg/kg, sc) after prophylactic treatment with atropine (1 mg/kg, sc) in normal saline and eserine (1 mg/kg, sc) in dimethyl sulfoxide. Control groups were treated with vehicle propylene glycol (0.1 mL/kg, sc), atropine in normal saline and eserine in dimethyl sulfoxide. The hens were sacrificed at different time points such as 2, 4, and 8 h, as well as 1, 2, 5, 10 and 20 days, and the tissues from cerebrum, midbrain, cerebellum brainstem and spinal cord were quickly dissected and frozen for protein (western) and mRNA (northern) studies. Subcellular fractionation, SDS-PAGE and immunoblotting of the nuclear and supernatant fractions using standard protocols from spinal cord and cerebrum showed differential expression of protein levels of PKA, CREB and phosphorylated CREB (p-CREB). There was an increase in PKA level in spinal cord nuclear fraction after 4 h (130 ± 5%) and 8 h (133 ± 6 %), while cerebrum nuclear fraction showed decrease (77 ± 5%) at 4 h and remained at the same level at 8 h. No change was seen in either spinal cord or cerebrum soluble fraction at any time points. There was an increase in CREB level in the spinal cord supernatant (133 ± 3%) after 5 days, while nuclear and supernatant fraction of the cerebrum did not show any alterations at any time point. p-CREB was induced in the spinal cord nuclear fraction at 1 day (150 ± 3%) and 5 days (173±±7%) of treatment, in contrast to the decreased levels p-CREB (72 ± 4%) at 10 days in cerebrum nuclear fraction. Supernatant fraction of spinal cord and cerebrum did not show any changes in pCREB at time points studied. Similarly another set of animals were treated with DFP and perfused using standard protocols and immunohistochemistry for p-CREB in the brain and spinal cord confirmed the overall protein expression pattern identified by western analysis. Expression of β-tubulin subtypes (1, 2, 3, and 4), studied by Northern blotting showed complex and differential pattern, while immunohistochemistry of the anti-β-tubulin for the entire period of OPIDN developmental stages showed early induction and persistence even in the disintegrating axonal and non-neuronal structures of the CNS. These data thus strongly suggest that early cytoskeletal damage at molecular level mediated by PKA/p-CREB pathways leads to the culmination of gross (microscopically observable) level cytoskeletal changes in various components of central nervous system (CNS), consistent with our earlier findings. Thus, the differential protein expression of PKA, CREB, p-CREB and β-tubulin subtypes appear to contribute to the initiation, progression and development of OPIDN, probably by recruiting other molecular pathways specific to various components of nervous system.
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Diisopropyl phosphorofluoridate (DFP) is an organophosphorus ester that produces organophosphorus ester-induced delayed neurotoxicity (OPIDN) in hens 7–14 days after a single s.c. dose of 1.7 mg/kg. In this study, hens were treated with a single dose of DFP (1.7 mg/kg, s.c.) 24 hr after [35S]methionine injection into the sacrolumbar region of their spinal cord, and killed 3, 7, 14, or 27 days post-DFP treatment. The rates of transport of labeled high (NF-H), medium (NF-M), and low (NF-L) molecular weight neurofilaments, and tubulin were faster in DFP-treated birds than in controls after 3 days. Subsequently, the rate of transport of these proteins started falling, so that the peaks of labeled proteins in control and DFP-treated hens were overlapping after 7 days. At 14 days, the peaks of NF-H, NF-M, and NF-L in treated hens were distinctly behind the corresponding peaks in control hens. This was again followed by an increase in transport of NF-H and NF-L, but not of NF-M, so that the labeled NF-H and NF-L showed the same pattern in control and treated hens after 27 days. The transient decrease in NF-H and NF-L axonal transport rate, and recovery correlated in a temporal manner with the previously reported increase of Ca2+/calmodulin-dependent protein kinase-mediated phosphorylation of neurofilament proteins and inhibition of calpain activity in the sciatic nerve in OPIDN. Proteinase inhibition has been reported recently to result in enhanced phosphorylation of neurofilaments in some cells. The present study suggests that the enhanced phosphorylation of neurofilaments by DFP-increased Ca2+/calmodulin-dependent protein kinase activity may be contributing toward alteration in NF axonal transport and the development of OPIDN.
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Diisopropyl phosphorofluoridate (DFP) is an organophosphorus ester, which produces organophosphorus ester-induced delayed neuropathy (OPIDN) in hen and other sensitive species. A single dose of DFP (1.7 mg/kg, sc.) produces mild ataxia in 7–14 days in hens, which develops into severe ataxia or paralysis with the progression of disease. OPIDN is associated with axonal swellings and degeneration of axons. This study was carried out to investigate the expression of neurofilament (NF) subunits in the spinal cord of DFP-treated hens. Hens were treated with a single dose of DFP and sacrificed 1, 5, 10, and 20 days post-treatment. Western blot analysis showed increased expression of middle molecular weight neurofilament protein (NF-M), and decreased expression of high molecular weight (NF-H) and low molecular weight (NF-L) neurofilament proteins in the 2 M urea extracts of spinal cord particulate fraction. These changes were observed within 24 h of DFP administration and persisted for 10–20 days. Thus, there was increase in the stoichiometry of NF-M:NF-L in the spinal cord of DFP-treated hens. Immunoprecipitation, cross-linking, and two-dimensional polyacrylamide gel electrophoresis showed the presence of heterodimers, but not heterotetramers, in the hen spinal cord extract. Immunohistochemical staining revealed the presence of all three NF subunits in the cytoskeletal inclusions in DFP-treated hen spinal cord cross-sections. The results suggested that each NF subunit might be accumulated by a different mechanism in the axonal aggregations of DFP-treated hen.